Aircraft Generator Clutch Shift Control for Stable Input Frequency
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Solution Overview
Problem
Large rotational frequency fluctuations in power output from aircraft engines cause instability in electric power generation, as existing solutions like large diameter continuously variable transmissions or small manual transmissions lead to size increases or momentary frequency changes beyond the response ability of downstream continuously variable transmissions.
Innovation Solution
A controller for an electric power generating apparatus with a manual transmission and a friction clutch actuator that maintains the clutch in a half-engaged state during gear shifts, allowing gentle output rotational frequency changes and stabilizing power input to the electric power generator, while a continuously variable transmission adjusts input frequency to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the speed change range of a continuously variable transmission is made large to handle large rotational frequency fluctuations, then the rotational frequency stability is improved, but the transmission diameter and apparatus size increase
Solution Approach 1:
The transmission system is divided into two segments: a manually operated transmission for coarse speed adjustment and a continuously variable transmission for fine speed control. This segmentation allows each component to be optimized independently, preventing the need for an oversized CVT while maintaining frequency stability.
Solution Approach 2:
The manual transmission acts as an intermediary between the engine and the CVT, pre-adjusting the speed to bring it within the optimal operating range of the CVT. This intermediary function reduces the speed adjustment burden on the CVT, allowing it to remain compact while ensuring stable power delivery.
2Volume of moving object
If a small manual transmission is provided upstream to narrow the rotational frequency fluctuation range, then the apparatus size is reduced, but momentary rotational frequency fluctuations occur during gear shifts that exceed the response ability of the downstream continuously variable transmission
Solution Approach 1:
The system performs preliminary speed adjustment through the manual transmission before power reaches the CVT. By pre-narrowing the rotational frequency fluctuation range, the CVT operates within its optimal response capability, preventing momentary instability during gear shifts.
Solution Approach 2:
The control system monitors the output rotational frequency of the manual transmission and adjusts the CVT ratio accordingly. This feedback mechanism ensures that when the manual transmission completes a gear shift, the CVT compensates for any momentary frequency changes, maintaining stable power generation.
3Adaptability or versatility
If a friction clutch is used to switch gear stages in the manual transmission, then the transmission can handle large rotational frequency fluctuations, but sudden clutch engagement causes momentary output rotational frequency changes
Solution Approach 1:
The clutch engagement process is divided into periodic stages: initial engagement, slip phase, and full engagement. During the slip phase, the clutch allows relative motion between input and output shafts, gradually transferring torque and smoothing out rotational frequency transitions during gear shifts.
Solution Approach 2:
The clutch slip ratio is dynamically adjusted during engagement based on real-time monitoring of input and output rotational frequencies. This dynamic control allows the clutch to adapt its coupling characteristics, maintaining stable output frequency while handling large input fluctuations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents momentary rotational frequency fluctuations and stabilizes electric power generation by controlling clutch pressure based on load and output frequency, maintaining constant input frequency to the electric power generator even with large rotational frequency fluctuations.
Implementation Method 1
a friction clutch pressed by an actuator
Data Source
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AI summary
An electric power generation controller for use in an aircraft is a controller of an electric power generating apparatus including a manual transmission configured to change speed of rotational power of an aircraft engine, transmit the rotational power to an electric power generator, and switch a gear stage by a friction clutch pressed by an actuator. The electric power generation controller includes a manual transmission control section configured to control the manual transmission. The manual transmission control section includes: a shift command section configured to output a shift signal which switches the gear stage of the manual transmission; and a clutch control section configured to, when switching the gear stage of the manual transmission, control clutch pressure of the actuator such that the friction clutch becomes a half-engaged state.